It could be a number of different fluids. As someone pointed out some commercial turbine oils like BP 2197 have a distinctive greenish tinge while
others like Mobil MJ2 are more an orange colour. I don't know what hydraulic fluid they are using on the F-22 but Skydrol LD-4 has a light purplish
tint to it when fresh but oxidizes and ages to a light honey colour. There are a number of different Skydrols though and its possible that there is a
Mil spec one with different colouring. My guess if it's something mundane is either that its turbine oil or hydraulic fluid, either reacting with the
RAM coatings or that the coatings on that aircraft have worn a bit and we are seeing the underlying primer showing through with the aforementioned
fluids on top.

As for the projection I'm theorizing either APU exhaust or it could be avionics cooling exhaust. That would explain why it was showing on the ground
in one of the pics posted. I also not that in one of Boomers pics there appears to be brown exhaust type staining behind it. Its possible that in
certain flight regimes or with specific equipment running that it also deploys in flight.

According to this drawing it looks like the hatch in question was the APU exhaust (146) with the intake hatch just ahead of it
(148).

alright so according to that diagram (probably from china. lol) the doors in question are in fact the apu exhaust and intake hatch. so thats solved.
But why is it open in flight? thats the bigger question.

And from that drawing the panel that is open on the top that looks like its spilling out green fluids is the engine bleed air primary heat exchanger.
To my limited knowledge of fighter design, isnt that something used on the ground as well? dont they use the bleed air to crank the engines?

Bleed air has a number of uses, the most common is engine start. It's also used for pressurization, which is why a leak allows fumes into the
cockpit/cabin. But I don't see them using green coolant for the heat exchanger. Green isn't the best for cooling or for length of life. Red tends to
last a lot longer.

Looking at where the greenish fluid is, I don't believe there's any way it can be an intentional route for something to be ejected to perform some
purpose. It's in a terrible place: between the two engine bulges would have detrimental effects on the dispersion of whatever it is. You would end up
with so much of the material within the boundary layer and just falling back onto the aircraft itself that it would just be terribly inefficient. If
you really wanted to get a spread, your best bet would be to locate the ejection at the very rear of the aircraft where it can catch properly
high-speed flow. I really am inclined to think that the green stuff is either a leak, or not a liquid. Can't say what it is much more than that
myself.

Lol I got a good laugh outa this and decided to go give NOTAM a google.... I ended up at some FAA site that made me click ok on a disclaimer....

Well I tried to go back but on my phone I couldn't click the button the accept window had precedence..... Soo I just clicked accept and then hit
back

I proceeded to read a wiki page and a few others regarding what NOTAM means but then a curious thing happened.. I tried to come back to ATS and boom
my phone quits working.

Instant closing of the browser.. Over and over again. I then went into my cookies through settings and managed to delete then and everything is ok now
butttt what exactly happened? Lol did I trigger some cookie that was trying to keep me from blabbing something i just read on the NOTAM site?

On topic... It definitely looks like copper corrosion. If Regis was asking me for a million dollars I'd have to go with copper being involved somehow.

NO TAMS is short for notices to airman. All pilots, military and commercial have to view the notams on their flight route. They give information like
restricted airspace and anything else that could hamper your flight.

According to this drawing it looks like the hatch in question was the APU exhaust (146) with the intake hatch just ahead of it
(148).

alright so according to that diagram (probably from china. lol) the doors in question are in fact the apu exhaust and intake hatch. so thats solved.
But why is it open in flight? thats the bigger question.

And from that drawing the panel that is open on the top that looks like its spilling out green fluids is the engine bleed air primary heat exchanger.
To my limited knowledge of fighter design, isnt that something used on the ground as well? dont they use the bleed air to crank the
engines?

The aft door that appears open is the APU exhaust. It only appears open. It won't open unless the forward door is also opened. Only way that can be
open just that small amount it looks like would be a part failure. As far as green fluid, I don't remember seeing green any where, but there are
possibilities. Nothing in that pictures seems out of the ordinary from every one I've been on top of.

a reply to: EasyPleaseMe
Yes Skydrol tends to eat a lot of standard materials used in more mundane hydraulic systems. That's why I tend to double glove when playing around
with it as after 5-10mins the standard disposable gloves simply fall apart. I didn't realize that military aircraft don't use it though. It was
designed in the early 50's because of its fire retarding properties so it seems odd that it isn't in military use where fire risk is probably far
greater.

I know my aviation fluids because I have had the very pleasant experience of having been sprayed, splashed and doused in most of them quite a few
times. I certainly DON'T recommend Skydrol. It burns eyes, lips and errr... other very sensitive body parts (thoroughly wash your hands BEFORE you go
to the toilet

). Imagine taking a fresh chilli and squeezing the juice into your eye and you get the picture and sensation, wonderful stuff!

"Applications
The key applications of copper oxide nanoparticles are as follows:

As burning rate catalyst in rocket propellant. It can greatly improve the homogeneous propellant burning rate, lower pressure index, and also perform
better as a catalyst for the AP composite propellant

Can be applied to the catalyst, superconducting materials, thermoelectric materials, sensing materials, glass, ceramics and other fields

Why do people keep going round and round with this? I already pointed out (many posts ago) that the green perfectly matches the anticorrosive
undercoat. Someone else kindly provided a photo that illustrated this. The apparently wet surface may be due to a bit of fuel left over after
air-to-air refueling.

I also clearly identified the protruding item as the APU exhaust panel. That is what it is without question. Do you want the panel number? The part
number? This is not an unidentified component. The only real question is why it might be open in flight.

I just had another look at these panels, and I honestly think the raised appearance of the APU exhaust is an optical illusion. I'm thinking it's
just a dusting of carbon soot around some of the port, and given some of the discolouration seen on the rest of the airplane I think it's been a
while since it has seen some exterior love.

Looking at the bottom pic where the door is clearly closed, there is also still a very visible dusting of black, which I'm again assuming is soot.
That being the APU exhaust it would make sense we see this only on the one side. If black crap is coming out of the intake, then something has
probably gone wrong.

I just had another look at these panels, and I honestly think the raised appearance of the APU exhaust is an optical illusion. I'm thinking it's
just a dusting of carbon soot around some of the port, and given some of the discolouration seen on the rest of the airplane I think it's been a
while since it has seen some exterior love.

Looking at the bottom pic where the door is clearly closed, there is also still a very visible dusting of black, which I'm again assuming is soot.
That being the APU exhaust it would make sense we see this only on the one side. If black crap is coming out of the intake, then something has
probably gone wrong.

Between that and the missing material. Yes it is an illusion. As I said earlier, this jet looks like all the others I've been on top of.

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